HAZARDS AND SOLUTIONS OF PIN HOLES IN SURFACE OF WIND TURBINE BLADES 22011-12-16
In addition to its structural factors, the factors causing water seepage of wind turbine blades also include the above-mentioned sand hole and coating crack. All the structural factors will not be discussed in this article. Because problems of coating crack are related to the entire coating accessory, they won't be discussed for the moment either. Sand hole is produced because of an impact of foreign particles on turbine blade, and pin hole in substrate surface under the compact of foreign particles continues to enlarge, and it is more likely to become large-diameter sand hole. Through eliminating pin holes, the formation of sand holes may be reduced to a certain extent. There are four common methods to eliminate pin holes after the formation of wind turbine blades: (1) to scrape the surface with pin hole repeatedly, through using a slice of major resin which is used to mold turbine blade. It is a simple and effective method, except that it’s too slowly to dry resin, which may affect the overall production schedule; (2) to repair with finish over and over again. The effect of this method is not good, with potential quality problems. Because finish contains solvents, finish solvents infiltrated into pin holes will cause solvent residue; (3) to get pin holes covered with solvent-free putty, and the thickness of putty is 500μ or more. Practice has proved that such method is simple and effective, but the putty is exposed to too thick blade coating, affecting the overall smoothness; (4) to repeat blade coating on pin holes with special-purpose micro pore putty, until the pin holes have been completely sealed up. The effect of this method is better and more apparent. The shortcoming is that, micro pore putty has higher requirements in operation precision; it is required to strictly carry out in accordance with construction process, and the larger substrate surface has no deficit repair function. The effect is best when the third and fourth methods are combined in the actual construction process.